The present invention is directed to a resealable conduit and method for removing or adding fluid to a closed system. The fluid can be of any type.
Physiological fluid samples in containers need to be easily accessible without compromising the integrity of the sample. Closed systems such as stoppered physiological fluid sample tubes are accessed to remove one or more aliquots of the fluid. Alternately, fluid can be added to the sample tube, such as when a dilution is desired. Various diagnostic and therapeutic tests can be performed upon the aliquots. Physiological fluids such as, for example, blood or urine are frequently collected and stored in sample tubes closed by a rubber or elastomeric material stopper.
Typically, fluid samples are removed from a stoppered tube by removing the stopper, inserting a pipette stem into the fluid, aspirating fluid into the pipette and replacing the stopper. This access method can create aerosols and exposes sample fluid to the local environment. Aseptic conditions can thereby be violated Biohazard can arise when this prior art fluid access method is used if the sample tube contains virulent or infectious organisms. These problems are compounded when the sample tube is reaccessed to remove further fluid samples.
A further problem is coring, which can occur when a hollow conduit is inserted through a rubber or like-material stopper. Coring is the removal of stopper material from the wall of the stopper as a hollow conduit is forced through the stopper. The cored material can enter the bore of the conduit thereby blocking it. Additionally, cored material can fall into the sample fluid when insertion of the conduit is complete, thereby contaminating the sample and rendering it unsuitable for analysis.
Needle tip conduits for piercing rubber septums or stoppers are known. These devices suffer from the disadvantages of coring, lack of a closure valve to prevent fluid backflow when tipped or inverted, high cost and inability to maintain essentially aseptic conditions.
Accordingly, there is a need for a low cost stored in closed sample tubes without coring and with maintenance of a high level of fluid asepsis. The device and method should permit repeatable access to such body fluids with minimal risk of creating aerosols, biohazard or contamination of either sample fluid or the sampling environment.